Anode



Patented Oct. 27, 1936 PATENT OFFICEv AN ODE George Lutz, Rocky River, Ohio, assignor to The Grasselli Chemical Company, Cleveland, Ohio, a corporation of-Delaware Application January 5, 1935, Serial No. 504

4 Claims. (Cl. 204-4) This invention relates to anodes, and is particularly directed to consumable anode units in the form of hollow cylindraceous figures, which anode units are supported in a perforate recep- '5 'tacle made of a material insoluble in a plating bath.

Those working in the art have found it desirable, under some circumstances, to employ composite anodes which comprise a perforate receptacle, which is insoluble in the plating bath, within which receptacle were placed soluble anode units having the form of spheres or sticks. In the course of plating operations, more of the units were added to the receptacle as required.

This practice has been none too satisfactory because a large amount of metal is required to fill the basket, and because the effective area of the anode tends to vary from the top towards the bottom of the solution.

It is an object of my invention to provide a composite anode which employs such anode units that, within limits, the ratio of the weight of consumable metal to the effective anode area can be varied at will. A further object of my invention is to provide an anode which has a relatively constant effective area from top to bottom. Other objects will become apparent hereinafter.

I accomplish my objects by the use of hollow anode units in a perforate, insoluble receptacle.

. In operation such a receptacle is filled with the anode units, and the composite anode thus formed is used, in known manner, as an anode in electro-deposition. After a time, the anode units are dissolved and diminished in size, and it be- 5 comes necessary to add more anode units to the receptacle. tion, the anode units are of successively smaller size from the top to the bottom of the receptacle: the units lower in the receptacle having been in use for a. longer period of time.

A hollow anode unit has an area greater than a similar unit which is not hollow. It should be noted that by hollow I mean that metal has been, in effect, removed from within a solid. The

total area oi a hollow figure is greater than that of unmodified figure, because almost all of the original area is effective, and, in addition, the area of the hollow is effective. By adjusting the size of the hollow, any desired ratio of weight to area may be obtained, within limits.

The area. of the anode units of my invention remains relatively constant. In the first place, as it is generally true that the area of a cylindraceous body decreases more rapidly than its volume with a-decrease in radius, I may avoid the After a considerable period of opera formation of low area units by hollowing out the ineilicient part. In the second place, the decrease in area caused by the dissolution of the outer surface is at least in part oiiset by the increase in surface area caused by dissolution 5 within the hollowed portion. The advantages and details of operation will be pointed out in more detail hereinaften In the drawing:

Figure l is a perspective view of a composite W anode according to my invention, a part of the View being broken to show anode units in place,

Figure 2 is a view similar to Figure 1, but showing a modified basket,

Figure 3 illustrates another modified basket, m

Figure 4 is a perspective view of an anode unit such as that used in the basket of Figure 1,

Figure 5'illustrates a modified form of anode unit,

Figure 6 shows another modified anode unit, and

Figure 7 shows a further modified anode unit. Considering the illustrative embodiments of my invention in more detail; in Figure 1 there is seen a preferred anode basket illustrated as containing 25 a number of unused anode units. The anode basket includes a wire helix which, as shown, has

a substantially uniform pitch and has substantial spaces between its convolutions. The helix l is closed at its lower end by a cup 2. The wire 0 helix l is welded to a strap 3 which is bent at its lower end to form a support 4. The wire helix l is welded to cup 2, and'cup 2, in turn, is secured to support t by a bolt 5. The upper end of strap 3 is bent to form a hook 6 which serves to support 35 the basket in a plating bath.

The hook 6 is preferably attached to a bus bar, and an electric current is distributed from the bus bar thru the strap 3, helix l, cup 2, and bolt 5. Anode units within the helix are thus electrically 40 charged.

The basket is made of metal, such as iron, steel, or lead, relatively insoluble in the plating bath in which it is to be used. The basket may, of course, be made in whole or in part of an insoluble, electrically non-conductive material, but in this event, provision must be made for contacting the anode units with a source of current. The basket, similarly, may be insulated as by coating the portion which will contact the bath with 50 rubber. In this event a contact is preferably provided at the bottom of the basket by leaving the inner end of bolt 5 uncoated so that an electric current may be carried to the anode units thru strap 3. w

Numerous other forms of baskets may be employed to hold my anode units. In Figure 2, for example, there is shown a modified basket which comprises a plurality of spaced, vertical wires 1 which define a vertical tube. The tube thus formed is closed at its lower end with a disc 8 to which the wires are secured in any desirable manner. The upper ends of the wires are held in the proper relative position by attachment to a ring 9. Anangle-bar i0 is fastened to the disc 8 and to the ring 9. The angle-bar l0 terminates at its 'upper end in a hook 6. The basket may be suspended in a plating bath by means of the hook 6.

The basket of Figure 2 may be made of any suitable material such as those above noted in connection with Figure 1. If the basket be all metal, the entire basket serves to distribute current to the anode units. If the basket be covered with an insulating material, the upper portion of disc 8 should be left uncoated so that a current may be carried from hook 6 to angle-bar ID to the anodeunits. Similarly, if the basket be constructed of a non-conductor, some provision must be made for carrying an electric current to the anode units.

The modified basket of Figure 3 differs from the basket of Figure 2 only in that the wires 7 are positioned as elements of an inverted, frustoconical figure. In the drawing, the extent of the increase in size from top to bottom is somewhat exaggerated for purposes of illustration.

As the anode units approach the bottom of the basket, they may collapse and break into fragments. In order to retain the fragments in the basket, it may be desirable to position the wires 1 rather close together. The spaces between the convolutions of the helix l of Figure 1 should, similarly, not be too great. To avoid the use of too much material in the basket, it may sometimes be desirable to make the spaces smaller near the bottom of the basket as by spacing the convolutions of helix I close at the bottom, or, particularly in the baskets of Figures 2 and 3, as by the interpolation of short, vertical wires, by the use of a number of spaced turns of wire, woven, or encircling, the bottom portion of the vertical wires, or by the application of a circumferential strip of foraminous material on the lower portion of the basket.

The basket of Figure 1 is illustrated as con-. taining a plurality of hollow cylindraceous anode units such as the one shown in Figure 4. The consumable unit of Figure 4 consists of a hollow cylinder which has a height equal to its diameter. The-cylinder is hollowed by a cylindrical opening whose axis coincides with that of the cylinder. A cadmium anode used with excellent results was one and three-eighths inches high, one and threeeighths inches in diameter, and had a center hole one-half inch in diameter. Minor changes in the form of the unit may be made to facilitate casting or fabrication. It may, for instance, .be desirable under some circumstances to make the cylinder and hollow slightly tapered to permi withdrawal of the unit from a mold.

Asseen in Figure 1, the anode units are placed so that the axis of one is substantially normal to the axis of the next. In this way the entire area of the units is accessible to the plating electrolyte. Of course, in practice it is not necessary that every anode unit be meticulously placed in the basket. Practically the whole area. of the units will be available if the units be at various angles to each other, and the whole area is more or less available even if the anodes be placed with the holes in vertical alignment.

The marked advantages of my anode units are apparent on a mere inspection of the drawing. The omission of the center portion results in a greatly increased area per unit of weight and in a more constant area of soluble anode metal from the top to the bottom of the basket. The decrease in area caused by dissolution of the outer portion of the cylinder is more or less ofl'set by f the increase in area caused by the increase in the diameter, and size, of the center hole. It will be apparent that the ratio of weight to area may be varied at will by varying the size of the hollow.

While the anode unit of Figure 4 has, to date,

proven the most satisfactory, I may use various other hollow anode units in combination with a perforate, insoluble receptacle. In Figure 5, for instance, the cylindraceous figure is not cylindrical but, rather, is elliptical in cross-section. The hollow is in the form of three cylindrical openings.

The opening, or openings, which make the figure hollow may, obviously, be of varied forms. In Figure 6, is shown, for instance, a cylindrical anode unit which is hollowed out with conical open-.

ings extending inwardly along the axis of the cylinder.

There is shown in Figure 7 a cylindraceous unit which has a center hollow of uneven contour. It is noted that the use of grooves on the surface of the figure does not, per se, constitute a part of this invention.

In Figure 8 there is seen a hollow anode unit which consists of a tetrahedron with a conformal hollow. It is noted that the use of tetrahedral units does not, per se, constitute a part of the present invention.

While in its broadest aspects my invention anode units.

As a practical matter, the advantages of my invention are best realized with a hollow, cylindraceous anode unit the greatest outside dimension of which does not greatly exceed three times the smallest outside dimension. Specifically, I prefer to use a hollow, cylindraceous anode unit the greatest outside dimension oi which does not greatly exceed twice the smallest outside dimension. More specifically, I prefer to use a consumable, hollow, cylindraceous anode unit the. height of which is substantially equal to its diameter. Also, as a practical matter, an anode unit should preferably be of such size and proportions that it could be inclosed in a sphere two or three inches in diameter.

The anode units are, of course, made of the metal which is to be electro-deposited. They may, for instance, be made of zinc. cadmium. zinc-mercury alloys, cadmium-mercury alloys, copper, and the like. I have found the anode units particularly desirable in connection with cadmium plating, and accordingly, my invention is particularly directed to the use of a cadmium, hollow, cylindraceous anode unit the greatest outside dimension of which does not greatly exceed three times its smallest outside dimension.

' While I have shown a number of specific forms of baskets and anode units, I do not intend to be limited thereby. The baskets may take various forms, and the hollow anode units, likewise, may assume various shapes and proportions. The anode units may also be varied in minor respects to facilitate casting or fabrication.

The scope of my invention will be more clearly apparent from the following claims.

I claim:

1. An anode for use in electro-deposition comprising a perforate, insoluble receptacle which contains a plurality of consumable, hollow, anode units arranged in a substantially single column and so arranged that the axes of the hollows are I unaligned.

2. An anode for use in electro-deposition comprising a perforate, insoluble receptacle which contains a plurality of consumable, hollow, anode units the greatest outside dimension of each of which does not greatly exceed three times the smallest outside dimension at the time the units are added to the receptacle, theunits being arranged in a substantially single column and so arranged that the axes of the hollows are unaligned.

3. An anode for use in electro-deposition comprising a perforate, insoluble receptacle which contains a plurality of consumable, hollow cylindraceous anode units having cylindraceous hollows along their axes, and theunits being arranged in a substantially single column and so arranged that the axes of the hollows are unaligned.

4. An anode for use in electro-deposition comprising a plurality of spaced, vertical, insoluble wires which define a vertical tube, the said tube being closed at its lower end and open at its upper end, the basket thus constructed containing a plurality of consumable, hollow, cylindraceous anode units arranged in a substantially single column and so arranged that the axes of the hollows are unaligned.

GEORGE L. 

